1. Field of the Invention
The present disclosure relates to an optical sensing frame, and more particularly, to an infrared sensor module capable of covering an optical signal region by change of a light receiving region, preventing noise through processing of blocks in the light receiving region which extends, and adjusting the light receiving region without physical adjustment thereof, to a touch sensing method of the infrared sensor module, and to an auto calibration method applied to the same.
2. Discussion of the Related Art
In general, a touch screen is one of various interface types between a user and an information and communication device, which uses various kinds of displays. Such a touch screen is an input device which enables the user to interface with the device as the user touches a screen with a hand or a pen.
The touch screen allows for a conversational and intuitive manipulation of the device, since it may be easily used by anyone by a touch of a button displayed on the display with a finger. Because of these features, the touch screen is applied in many fields, such as issuing machines in banks and public agencies, various medical devices, tour and major facility guidance devices, and traffic guidance devices, in addition to monitors and televisions which are personally used.
Various types of touch screens are available, such as a resistive type touch screen, a capacitive type touch screen, an ultrasonic wave type touch screen, an infrared type touch screen, and so on depending on ways of perception used.
Although the above types have different advantageous, the infrared type touch screen is recently drawing attention due to a minimized pressure required to be applied to a touch surface, and convenience of arrangement.
Hereinafter, a conventional optical type touch screen will be described with reference to the attached drawings.
FIG. 1 is a top view illustrating a display module and infrared sensor modules arranged at outer corners thereof, in the conventional optical type touch screen.
As shown in FIG. 1, the conventional optical type touch screen is constructed in such a manner that the infrared sensor modules 2a and 2b are arranged at the outer corners of the display module 1. Although not shown, retro-reflection plates (not shown) are located at all three sides of the display module 1 except for a horizontal line which connects the infrared sensor modules 2a and 2b. 
The infrared sensor modules 2a and 2b are coupled with a separate assembly (not shown) from the display module 1, and reinforced glass are arranged at a lower portion of the infrared sensor modules 2a and 2b to be located on the display module 1. The reinforced glass functions as a touch input surface which enables a direct touch of a user.
Here, each of the infrared sensor modules 2a and 2b is located at the outer corner of the display module 1, and has a light receiving portion for sensing light which is incident in a horizontal direction at each position thereof.
During detection of the touch, each of the infrared sensor modules 2a and 2b receives light which is incident from a coordinate input area at each position thereof so as to enable a coordinate of an object in the coordinate input area to be recognized through measurement of light quantity distribution. It is important that the light receiving portion is fixedly located on a surface of the reinforced glass which functions as the touch input surface. Because an optical signal is not fully received to the light receiving portion when each infrared sensor module deviates in position. In this case, since recognition of the object is difficult in the coordinate input area, the touch may not be perceived or erroneous perception of the touch may occur.
However, the conventional optical type touch screen as described above has the following problems.
In general, each of the infrared sensor modules includes the light receiving portion in the form of a line sensor having a plurality of pixels in line. In this case, when the infrared sensor module originally deviates in position during assembly of the infrared sensor module or a position of the infrared sensor module deviates due to elapse of time or impact of products, the received optical signal may actually depart from the light receiving portion of the infrared sensor module. Therefore, touch sensitivity is deteriorated, or a touch position is normally not perceived.
In order to prevent this problem, it is considered to enlarge a size of the light receiving portion in upward and downward directions and in left and right directions allowing for deviation in the position of the infrared sensor module. However, this has a problem in that the touch screen increases in thickness and in outer area by increase in volume of the infrared sensor module. In addition, there is a problem in that the light receiving portion is widely arranged at a larger space than actually the required space, thereby processing an increased amount of transmission.